The present invention relates to an autostereoscopic display apparatus by use of a parallax in a one-dimensional direction.
There are conventionally-known methods for displaying different images depending on viewing positions by segmenting an image in a display apparatus such as a printing surface and a liquid crystal panel in multiple viewing directions by use of particular optical members, for example, lenticular lenses, slit-type barriers and lens arrays. In particular, different display images (parallax images) having a particular parallax with respect to an identical object are configured to be input to the respective right and left eyes. Accordingly, a stereoscopic image display apparatus capable of stereoscopic viewing without eyeglasses (hereinafter, referred to as “an autostereoscopic display apparatus”) is realized. Note that, in the present application, a direction to segment an image in a display apparatus into parallax images is principally one dimension in a horizontal direction.
In the case of carrying out stereoscopic viewing by use of an autostereoscopic display apparatus, an image in the display apparatus is required to be segmented into parallax images in many directions as much as possible to increase viewpoints, so as to extend a viewing range capable of stereoscopic viewing, and so as to achieve a natural stereoscopic effect and smooth motion parallax for allowing for long hours of viewing.
In recent years, applications of stereoscopic viewing by use of parallax images to digital signage, car navigation systems and the like are being considered for eye catching and visual recognition improvement. In order to achieve such applications, even when a low-resolution display apparatus is used, an image in the display apparatus is required to be segmented into parallax images as finely as possible to carry out natural stereoscopic viewing.
As a measure of such a requirement, segmenting a viewpoint as finely as possible is an effective way so that a viewer can view any of the segmented viewpoints (a multi-view system), rather than segmenting the viewpoint while assuming a location of the eyes of the viewer in space. In order to increase the segmentation number of the parallax images, increasing a lens pitch with respect to a pixel pitch of the display apparatus is effective. However, in this case, resolution of the parallax images in a lens pitch direction is significantly reduced since color subpixels are magnified due to a magnification effect of lenses in proportion to the increase of the lens pitch. As a result, a problem of a difference in resolution between a horizontal direction and a vertical direction is caused.
In Patent Document 1 (Japanese Patent Unexamined Publication No. 09-236777), lenticular lenses are inclined with respect to a pixel array so as to compose one three-dimensional pixel by use of subpixels in a vertical direction in addition to subpixels in a horizontal direction. Patent Document 1 has reported that a reduction in resolution of a three-dimensional view is thus prevented, and the balance of the resolutions in the horizontal direction and in the vertical direction can be improved.
In view of coexistence with a two-dimensional view and a matter of cost, an autostereoscopic display apparatus is being required, which uses a widely prevalent display apparatus including color subpixels of R (red), G (green) and B (blue) in which the color subpixels of each color are orderly arranged in a vertical direction.
Patent Documents 2 (Japanese Patent Unexamined Publication No. 2005-309374) and 3 (Japanese Patent Unexamined Publication No. 2006-048659) teach an equal arrangement of color subpixels of each of three colors in each line in a horizontal direction while focusing on an inclined angle of lenticular lenses with respect to a display apparatus. It has been reported that unevenness of color and luminance can be decreased due to such a constitution even when using a display apparatus in which color subpixels of different colors, for example, color subpixels of respective R (red), G (green) and B (blue) different in a horizontal direction are arranged in rows in a vertical direction in a stripe state. In addition, FIG. 1 of Patent Document 2 shows a constitution in which a lens pitch of the lenticular lenses is 7/2 of a pixel pitch so that seven segmented parallax images are arranged across two lenses in the horizontal direction. Therefore, when the lens pitch is deviated from the integral multiple of the pixel pitch, a fine segmentation of the parallax images in multiple directions can be achieved even if the lens pitch is small. Accordingly, it is possible to deal with the problem and requirement described above.